Marine propulsion means



Sept. 25,1962 F. c. CLARK 3,055,175

MARINE PROPULSION MEANS Filed March 14, 1961 5 Sheets-Sheet 1 Uta:

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MARINE PROPULSION MEANS Filed March 14, 1961 5 Sheets-Sheet 4 Sept. 25, 1962 c, CLARK 3,055,175

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o \o so so so no IZO no 1519- no I60 PUMP INPUT HORSE POWER OR ENGINE HORSEPOWEK Q 2 so a Q! g 40 I O (D 5Q F:-$J

g 30 E y A= PUMP DISCHARGE AREA H= APPLIED HORSEPOWEK M 20 3 g A lav-"H a a :0 Z I D 1 l i 1 O \O 2.0 3O 4 50 60 7O 8O 90 I00 PUMP INPUT HORSEPOWER OR W meme HORSEPOWER :PQKK csak(\ w AJ -41 JAI J a 1 7% Qflwomsv/ United States Patent Ofifice 3,055,175 Patented Sept. 25, 1962 3,055,175 MARDIE PROPULSION MEANS Frank C. Clark, 47 W. Bay Drive, Cocoa Beach, Fla. Filed Mar. 14, 1961, Ser. No. 95,761 7 Claims. (Cl. 60-3555) This invention relates to marine propulsion means and particularly to marine jet motors in which a pump issues a jet of water to propel the boat.

The general object of the invention is to provide a new and improved marine propulsion means of the above character which, as compared to prior arrangements, increases the speed, reduces the drag, and in general, operates with greatly improved efiiciency.

A more detailed object is to achieve the foregoing by discharging the propelling jet of water above the water into the air.

Another object is to improve the efficiency by discharging the water into the air in a large volume but at a low velocity.

The invention also resides in the novel means for controlling the direction in which the jet motor acts and for turning a boat equipped with the motor.

Other objects and advantages of the invention will become apparent from the following detailed description taken in connection with the accompanying drawings, in which FIGURE 1 is a fragmentary side elevation of a boat equipped with an outboard motor embodying the novel features of the present invention.

FIG. 2. is an enlarged side view with parts broken away and shown in section.

FIG. 3 is a sectional view taken along the line 3--3 in FIG. 2.

FIG. 4 is a fragmentary sectional view taken along the line 44 in FIG. 2.

FIG. 5 is a sectional view taken along the line 5--5 in FIG. 4.

FIG. 6 is a fragmentary sectional view taken along the line 6-6 in FIG. 4.

FIGS. 7 and 8 are fragmentary sectional views similar to FIG. 3 but show the parts in different positions.

FIG. 9 is a perspective view of the mechanism for controlling the direction of movement of the boat.

FIG. 10 is a graph showing the relationship of the discharge area of the pump and the horsepower applied to the pump.

FIG. 11 is a graph showing the pump discharge area per horsepower as a function of horsepower.

While the invention is equally applicable to so-called inboard marine motors, it is shown in the drawings, for purposes of illustration, as incorporated in an outboard motor. Specifically, the invention relates to motors designed for use with speed boats as contrasted with larger ships, such as ocean-going vessels and the like. Such a motor usually includes a power head 10, which normally is a gasoline engine, secured to a boat 11 through -a suitable clamp 12. Depending from the power head is a casing 13 which houses the means for actually propelling the boat.

Herein, the propulsion means comprises a centrifugal pump whose impeller 14 (FIG. 2) issues a jet of water from an outlet 15 (FIG. 3) opening rearwardly in the casing 13. The reaction force produced by the jet propels the boat. On the suction side of the pump is a tubular conduit 16 which serves as the water inlet for the pump. The inlet is rigid with the lower end of the casing 13 and projects downwardly into the water and coaxially with the impeller 14. The inlet then curves forwardly to face in the direction of movement of the boat so that, when the :boat is moving forwardly, water enters the inlet with a ram effect. As shown the drawings, the inlet may be made of a yieldable material such as synthetic rubber so that it may yield without breaking should it encounter an underwater obstruction.

In accordance with the present invention, the propulsion means is constructed and arranged in a novel manner so as to increase the speed, reduce the drag caused by the motor, improve the efficiency and, in general, provide a commercially feasible jet marine mot-0r. To these ends, the impeller 14- is arranged to discharge the jet of water into the air, that is, above the waterline thereby reducing underwater friction and raising the thrust line to maintain the boat at the proper attitude. (As used herein, the terms waterline and waterlevel refer to the actual level of the water around the outlet 15 even though this level may be below the normal level of the water in which the boat is moving.)

Additionally, the water is discharged into the air in'a' large volume but at a low velocity relative to the boat being propelled. Preferably, the velocity is only slightly higher than the desired maximum speed of the boat. This \resul-tsin a substantially higher thrust or driving force for a given power input and, by discharging such a large volume-low velocity stream into the air, there is a marked improvement in the performance as compared with prior attempts at motors of this type.

In the present instance, the casing 13 is disposed wholly above the water, as shown in FIG. 1, and is in' the form of a scroll such as usually is used in centrifugal pumps. The central axis a of the casing is arranged vertically and the outlet portion 17 extends rearwardly and tangentially. An annular flange 18 (FIG. 2) upstanding from the cas-' ing is bolted to the underside of the power head 10 and secures the casing to the latter.

The impeller 14 is disposed within the lower half of the casing '13 along the axis a and is fast on the lower end of a vertical shaft 19. The shaft is jou-rnaled in the casing by means of anti-friction bearings 20 and projects up ward-1y to a point within the flange 18. A spur gear 21 on the upper end of the shaft 19 meshes with a pinion 22 on the output shaft 23 of the power head 10 and completes the drive connection to the impeller. The latter is of the type conventionally employed in centrifugal pumps and comprises four reversely inclined vanes 24 projecting from a hub 25 which is secured to the shaft 1 Herein, the pump employed is of the so-called mixed flow type and, for this purpose, the interior of the casing 13 is divided into upper and lower chambers 26 and 27 (FIG. 2) by a wall or partition 28. As shown in FIG. 3, the wall begins at 29 at the side of the casing opposite the outlet 15 and extends through approximately 180 degrees, terminating at 30 at the beginning of the outlet. The wall 28 at 29 substantially merges with the bottom of the casing and, from this point, the wall slopes upwardly for about degrees where it becomes level and extends hori-' zontally midway between the top and bottom of the casing. A circular wall 31 surrounding the shaft 19 closes the upper chamber 26 from the impeller 14 along that half of the chamber near the outlet 15.

With the foregoing arrangement, each vane 24 of the impeller 14 forces water onto the top of the wall 28 and into the upper chamber 26 as it turns from the start of the scroll 13 (the point 32 in -FIG. 3) to the end 29 of the wall 28. Continued turning of the vane forces part of the water under the wall and into the lower chamber 27 while the remaining part is pumped into the upper chamber. As the vane turns through the 90 degrees following the wall end 29, more and more water enters the lower chamber while less enters the upper chamber until the vane reaches the point where the upper chamber is closed oif from the impeller by the cylindrical wall 31. From this. point, all of the water is pumped into the lower chamber. As a result of this pump construction, the outlet 15 tends to. flow full thus producing a large volume jet of water. While a mixed flow pump as described above is a conventional type, it should be understood that, to obtain the best results for the present purpose, the pump should be constructed in accordance with well-known design principles to obtain maximum efficiency under conditions of high capacity and low total dynamic head.

' As an example of the volume and velocity of the jet discharge, a 14 horsepower head might be employed with a pump whose outlet 15 has a 24 square inch area.

,In such a case, the velocity of the jet stream would be about 36 feet per second, the velocity varying somewhat above or below this value depending upon the speed of the boat. The relationships of the horsepower and the discharge area of the outlet is shown by the curves in FIGS. 10 and 11. The curve 50 in FIG. 10 is defined by the equation:

1 A=10VF1 where A is the discharge area of the outlet 15 in square inches and H is the horsepower of the engine 10, that is, the horsepower applied to the pump. The curve 50 represents the practical lower limits which will produce the large volume and low velocity discussed above, any values above the curve being satisfactory. The foregoing example of a 14 horsepower head and a 24- square inch outlet falls at the point B on the curve 50.

Another way of expressing the proper relationships is shown by the curve 51 in FIG. 11. This curve is defined by the equation: rot H (2). H where R is. the ratio of pump discharge area per applied horsepower and H is the applied horsepower. As in the case of the curve '50, the curve 51 represents the lower practical limits andthe point E. designates the example described above.

In order to. control the forward motion of the boat, means are provided to open and close the outlet 15 and thus start and stop the boat. Preferably, this means. may alsobe. rendered effective to reverse the direction of flow of water from the outlet. to drive the boat backward. In the present. instance, this means comprises a pair of control elements 33 which may be moved selectively from a position completely closing. the outlet to a position in which the outlet is fully open and to a. third position in which the. elements deflect the. jet and reverse the direction of. flow of the. water so. that. the water is directed forand causes the boat to move backward.

As shown. in the drawings, particularly FIGS. 3, 5, 7 and 8.. the control elements 33 may take the form of arcuate vanes: which are. partial. cylinders. In the illustrated form, of the invention, the vanes 33 extend through an angle. of. I35; degrees and are mounted vertically to span the top and.- bottom walls of the outlet 15. The axes b of the. vanes are alined with the side walls. of the outlet and are supported to turn about these axes: by stub shafts 35 and 35 (see FIG. 9) which are iournaled in the casing13.

The radius of each vane is substantially equal to half the width of the outlet and the axes of the vanes are spaced from the ends of the side walls of the outlet by a distance equal to this radius.

With this arrangement, the vanes 33 may be turned to the position shown in FIG. 3 in which they are tangential to each other at the center of the outlet 15 and extend around to the side walls of the outlet. In this position, the outlet is substantially closed preventing the discharge of water. This, then, is the neutral position of the vanes. -As the vanes are swung forwardly, they progressively open the outlet until the vanes are disposed wholly to one side of the outlet (see FIG. 7). In this position of the vanes, the full jet stream is discharged and this, therefore, is the. forward position of the vanes. If the vanes are swung back degrees from the neutral position, they assume the position shown in FIG. 8. This is the reverse position and, in this position, each vane turns a portion of the jet stream through degrees to direct the stream forwardly and somewhat laterally as indicated by the arrows in FIG. 8. With the jet flowing in this direction, the boat moves rearwardly.

To position the vanes 63 selectively, the latter are turned by moving a handle 34 which is secured to a cross plate 34*. The plate spans and is bolted to the forward ends of parallel rack bars 36which slide horizontally in slots 37 (FIG. 4) in the casing 13 and have teeth meshing with spur gears 38 fast on the shafts 35 At their forward ends, the racks are guided by clamps 36 which are bolted to the casing. Moving the handle 34 forward and back slides the racks and thus turns the vanes 33 about their axes b. In order to indicate to the operator when the vanes are in one of the three principal positions and hold the vanes in the selected position, yieldable detents 39 (FIG. 6) engage notches 40 in the sides of the clamps 36 The detents may be in the form of balls located in holes 41 in the racks and are urged toward the clamps by compression springs 42. There are three notches 40 in each clamp, one corresponding to each position of the vanes. Thus, the engagement of the detents with one of the notches indicates the position of the vanes and serves to hold the racks and hence the vanes in the desired position.

Means is provided to control the turning movement of the boat and, preferably, achieves this by deflecting the water stream being discharged through the outlet 15. Herein, this means comprises a rectangular deflector plate or baflle 43 (FIGS. 3 and 9-) which is vertically disposed within the outlet. By means of trunnions 44, the deflector is pivotally supported on the casing 13 to turn about a vertical axis 0 which is centrally disposed in the outlet and is disposed slightly forward of the center of the deflector. When the latter is in the central plane of the outlet as shown in FIGS. 3 and 9, the water is discharged straight back and the boat moves forward. By turning the deflector about the axis 0 to the position shown in full in FIG. 7, more water is deflected to the left side of the outlet than to the right. This produces a resultant force tending to swing the stern of the boat to the right and thus turn the bow to the left. When the deflector is on the. other side of center (broken line position in FIG. 7), the boat is turned to the right in a similar manner.

In the present instance, the deflector 43 also is turned under the control of the handle 34. To this end, the inner end of the handle is supported on the plate 34 through the medium of a disk 45 which is journaled in the plate. A bar 46 secured to the disk projects rearwardly from the. plate and its free end is joined to one end of a horizontal link 47 through a pin and slot connection 48, 49. The other end of the link is secured rigidly to the upper trunnion 44. Thus, the handle turns the deflector through the disk 45, the bar 46 and the link 47.

It will. be observed that a marine motor constructed in accordance. with the invention is eflicient and practical in operation. Themotor produces a comparatively high thrust for a given power input and operates at a rather high efliciency throughout the range of normal speeds.

This application is a continuation-in-part of my copending application Serial No. 509,315 filed May 18, 1955.

I claim as my invention:

1. Marine propulsion means for a speedboat, said propulsion means comprising a casing, means for securing said casing to the boat with a least a portion of the casing disposed above the waterline of the boat, said casing having an outlet opening rearwardly and disposed above said waterline, means defining a water inlet disposed beneath said waterline and communicating with the interior of said casing, a pump disposed within said casing and operable to discharge water through said outlet, and an engine driving said pump, the area of said outlet in square inches being at least equal to ten times the cube root of the horsepower of said engine whereby said pump discharges a large volume of water through the outlet at a comparatively low velocity to propel the boat.

2. Marine propulsion means comprising a casing, means for securing said casing to a boat with at least a portion of the casing disposed above the waterline of the boat, a centrifugal pump having an impeller mounted to turn about a generally upright axis and disposed within said casing above said waterline, means defining an inlet opening outwardly below the waterline and communicating with the interior of said casing adjacent said axis, said casing defining a spiral chamber extending around said axis and terminating in an outlet which opens rearwardly, a spiral wall in said chmber having one end in said outlet between the upper and lower edges thereof and inclined downwardly toward the bottom of the casing, and a power actuator operable to turn said impeller in the direction of the spiral to pump water into said chamber both above and below said wall to discharge a large volume of water through said outlet to propel the boat, the area of said outlet in square inches being at least equal to ten times the cube root of the horsepower of said engine.

3. Marine jet propulsion means having, in combination, a casing adapted to be mounted on a boat, a pump disposed within said casing, means defining a water inlet in said casing for said pump, said casing having a rearwardly opening conduit forming an outlet through which water is discharged in a jet by said pump to propel the boat, power operated mechanism for driving said pump, a pair of vanes each formed as part of a cylinder and extending through an angle greater than 90 degrees, and means supporting said vanes to turn about parallel axes disposed in the planes of the opposite sides of said conduit and extending through the longitudinal centers of the vanes, the radius of the vanes being approximately equal to half the width of said conduit and the sides of said conduit terminating short of said axes by a distance approximately equal to said radius whereby the vanes may be turned selectively to positions respectively closing the outlet, alongside the outlet and across the outlet to reverse the direction of the water discharged therefrom.

4. Marine propulsion means comprising a casing adapted to be mounted on a boat, a pump disposed within said casing, means defining a water inlet in said casing for said pump, said casing having a rearwardly opening outlet through which water from said pump is discharged in a jet to propel the boat, power operated mechanism for driving said pump, two control elements mounted adjacent said outlet on opposite sides thereof and movable from a first position across the outlet to a second position alongside the outlet thereby to control the discharge of Water and hence the forward movement of the boat, each of said elements when in said first position blocking half of said outlet and reversing the flow of discharged water, a deflector disposed within said outlet adjacent the center thereof and movable selectively to deflect a major portion of the water jet laterally in one direction or the other and thereby deflect discharged water toward a selected one of said elements when the latter are in said first position and to deflect the water laterally relative to said outlet when the elements are in said second position, said deflector being disposed forwardly of said elements to provide both forward and reverse thrust steering, and manually operable means connected to said elements and to said deflector and operable selectively to move the elements and deflector.

5. Marine jet propulsion means having, in combination, a casing adapted to be mounted on a boat, a pump disposed within said casing, 'means defining a water inlet in said casing for said pump, said casing having a rearwardly extending conduit with an outlet through which water is discharged in a jet by said pump to propel the boat, power operated mechanism for driving said pump, a pair of vanes each formed as a part of a cylinder and extending through an angle greater than degrees, means supporting said vanes to turn about parallel axes disposed along opposite sides of said outlet and extending through the longitudinal centers of .the vanes, the radius of the vanes being approximately equal to half the Width of said outlet whereby the vanes may be turned selectively to a first position alongside the outlet with the vanes forming a continuation of said conduit and a second position across the outlet to reverse the direction of the water discharged therefrom, and a manual control member operable to turn said vanes in unison but in opposite directions.

6. Marine jet propulsion means having, in combination, a casing adapted to be mounted on a boat, a pump disposed within said casing, means defining a water inlet in said casing for said pump, said casing having a rearwardly extending conduit with an outlet through which water is discharged in a jet by said pump to propel the boat, power operated mechanism for driving said pump, a pair of vanes each formed as a part of a cylinder and extending through an angle greater than 90 degrees, means supporting said vanes to turn about parallel axes disposed along opposite sides of said outlet and extending through the longitudinal centers of the vanes, the radius of the vanes being approximately equal to half the width of said outlet whereby the vanes may be turned selectively to a first position alongside the outlet with the vanes forming a continuation of said conduit and a second position in which said vanes meet and block both the sides and the end of said outlet and a third position in which the vanes extend across the outlet to reverse the direction of the water discharged therefrom, and a manual control member operable to turn said vanes in .unison but in opposite directions.

7. Marine jet propulsion means having, in combination, a casing adapted to be mounted on a boat, a pump disposed within said casing, means defining a water inlet in said casing for said pump, said casing having a rearwardly opening outlet through which water from said pump is discharged in a jet to propel the boat, power operated mechanism for driving said pump, two arcuate control elements mounted in said outlet to turn about vertical axes disposed on opposite sides of said outlet and move from a first position closing the outlet to a second position alongside the outlet and to a third position eflective to intercept said jet and change the direction of the latter, said elements being operable in said first position to prevent the discharge of water through said outlet and in said second position to permit rearward discharge of the water and hence forward movement of the boat and in said third position to cause forward discharge of the water and hence rearward movement of the boat, a deflector disposed within said outlet adjacent the center thereof for selective turning to deflect a major portion of the water laterally in one direction or the other and thereby cause the boat to turn, said deflector being disposed forwardly of said elements to turn the boat in the diflerent 7 8 positions of the elements, a member'mounted for manual 55,773 Kinkel et all lune 197 1866 movement longitudinally of said boat and also for swing- 164,03 3 Pratt June 1, I875 ing about a predetermined axis,'a connection between 543,182 Hunt July 23,, 1895 said member and said elements. operable upon lon im, 1,838,354 Bauen Dec. 29, 1931 dinal movement of the member to move the elements 5 2,024,274 Campmi -..--V Dee. 17,, 19.35 selectively to. oneof said positions; and, a second, con 2,149,155 Anderson Feb. 28, 1939 nection joining said member and. said deflector and op- OTHER REFERENCES erable upon swinging at the member to turn the deflector.

7 Flight Magazine (advertisement facing gage 60), Ian. References Cited in the file of, this patent 10 1944- UNITED STATES PATENTS 44,584 Pagenstecher Oct. 4, 1864 

